// e19
@Grab(group='joda-time', module='joda-time', version='2.0')
import org.joda.time.*

date = new LocalDate('1901-01-01').withDayOfWeek(DateTimeConstants.SUNDAY)
end = new LocalDate('2000-12-31')
total = 0
while (date <= end) {
    if (date.dayOfMonth == 1) total++
    date = date.plusWeeks(1)
}
println "==> $total"
